FIELD OF THE INVENTION
The present invention relates to a machine tool for storing a position and an attitude of desired points on a workpiece and automatically moving a jig with respect to a stationary machining head and, more particularly, to a machine tool capable of teaching a position and an attitude of a jig to a machining head while maintaining the machining head stationary.
The conventional machine tool of this type is shown in FIG. 1 wherein 1 designates a machining head fixed to a base table and 2 a workpiece to be machined which is fixed to a jig 3. The jig 3 is constructed to change its own position and attitude in accordance with control commands from a control system 4, a driving unit 5 for driving the jig 3 in accordance with the control commands from the control system 4, and a teaching box 6 for remotely controlling the jig 3.
The operation of the machine tool will be described below. The teaching box 6 is manipulated to operate the jig 3 such that the workpiece 2 takes the position and the attitiude fixed with regard to the machining head 1 at the point to be machined. Once the position and attitude of the workpiece 2 are determined with regard to the machining head, the teaching box instructs the control system 4 to store data being representative of the position and attitude of the machining head.
The control system 4 calculates to adjust the points beforehand stored and instructs the driving unit 6 to control the jig 3 to move to the calculated positioned and attitude when the control system receives playback commands.
The conventional machine tool is constructed as stated above. Therefore, the jig has to be moved such that the workpiece may be in the adequate position and attitude with respect to the stationary machining head when the jig is provided with information representative of its position and attitude with regard to the stationary machining head. Thus, the problem arises in that it becomes difficult to position a three-dimension configuration at a machining point fixed with respect to the machining head and difficult to detemined the attitude of the three-dimension configuration in a fixed direction to the machining head and, therefore, difficult to teach the fixed point to the jig, thereby requiring much time.